In the last decade, tumor specific peptides receive great attentions, and great efforts are devoted to relevant research, such that the tumor specific peptides become a promising imaging agent and therapeutic agent for tumors. However, the existing tumor specific peptide is a monospecific peptide for tumors, which suffers from some problems and disadvantages during practical use, including (1) lower specific binding to tumor than that of antibody-based therapeutics; (2) short retention time in organisms, and undesirable pharmacokinetic properties; (3) large change and uncertainty of biomarkers and receptors on the tumor cells occurring during the development of tumor cells, thus causing undesirable imaging effect.
In view of this, there is an urgent need in the art for an improved specific peptide, to overcome the defects in the prior art.